METHODS OF CONTROLLING TOBACCO INSECTS. 7 



the southern species is much the most abundant. These two species 

 arc so nearly alike in their work, life history, and seasonal history that 

 the remedial measures which apply to one will apply equally well to 

 the other. The life history and seasonal history notes given in this 

 article are from observations upon the southern species (Phlege- 

 thontius sexta Joh.). 



LIFE HISTORY AND SEASONAL HISTORY. 



This circular does not propose to describe in detail the life history 

 and seasonal history of the tobacco worms, but to give only such data 



Fig. 7. — The Southern tobacco hornworm (PMegethontius sexta): a, Adult; 6, larva; c, pupa. (From 



Howard.) 



as are necessary for the proper understanding of the reasons for 

 recommending certain methods of control. 



The tobacco moths begin to emerge from hibernation about June 

 1, and in a few days more they begin to deposit eggs. By reference 

 to Table I it will be seen that the eggs hatch in about 4 days, and that 

 the ''worms," or larva 3 , in from 19 to 20 days, pass through five stages 

 of growth. They then enter the soil to pupate (fig. 8). Those that 

 pupate not later than the last week of July will emerge in about three 

 weeks as adult moths of the second generation, and will commence 

 40704— Cir. 123—10 2 



